The document discusses the components of an entity-relationship (ER) model including entities, attributes, and relationships. It defines entities as objects, people, or places. Attributes describe an entity's properties. Relationships show how entities relate to each other, such as one-to-one, one-to-many, many-to-one, and many-to-many. The ER model develops a conceptual design for a database using these components depicted in an ER diagram.

1. ER-MODEL WITH DBMS
KOMAL
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2. CONTENT :-
• DBMS
• ER-MODEL
• DIGRAM COMPONENTS
• EXPLAINING OF :-
* ENTITY
* ANTRIBUTES
* RELASHIONSHIP
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3. DBMS :-
• It stans for Data Base Management System .
• It is used for creating and managing the database .
• It is a type of software used for store , retrieve, and
queries on data .
• It is a interface between end-user and database .
• It allows the user to create , read , update and delete data
in the database .

5. ER-MODEL

6. ENTITY RELATIONSHIP
• Entity relationship is also called ER-Model .
• It is a high level model .
• This model is used to define the data elements and relationship for a specified system .
• It develops an conceptual design for a database.
• It is also develops very simple and easy design to view of data .
• In ER modeling , the database structure is portrayed as a diagram is called as Entity –
Relationship diagram.

7. COMPONENTS OF ER-
MODEL DIGRAM :-

8. ENTITY :-
• An entity may be any object , person or place .
• In ER-Model diagram , Entity can be represented as rectangle symbol .
Rectangle

9. WEAK ENTITY :-
• An entity that depends on another entity is called weak entity .
• In ER-Model diagram, the weak entity is represented as double rectangle symbol .
Double Rectangle

10. ATTRIBUTE :-
• The attribute is used to describe the property of entity .
• For example :- Name , Age, Contact no. , Id , etc . Is attributes of the student.

11. KEY ATTRIBUTE :-
• The key attribute is used represent the main character of entity .
• The key attribute is represented by an ovel shape with the
text underline .

12. COMPOSITE ATTRIBUTE :-
• An attribute that composed of many other attributes is known as composite
attribute .

13. MULTIVALUED ATTRIBUTES :-
• An attribute can have more than one value is known as multivalued attribute .
• It is represented as double oval .
Double oval

14. DERIVED ATTRIBUTE :-
• An attribute that can be derived from another attribute is called derived attribute .
• It can be represent as dashed oval .

15. RELATIONSHIP :-
• An relationship is used to describe the relation between entityes .
• The diamond shape is used to represent it .
• It has two types :-
* Many-to-one relationship
* Many-to-Many relationship
* One-to-many relationship
* One-to-one relationship
RELATIONSHIP

16. ONE-TO-ONE RELATIONSHIP :-
• When only one instance of entity is associate with relationship, is called one-to-many
relationship .
• For example :- A female is marry to one male , and one male is marry to one female .

17. ONE-TO-MANY RELATIONSHIP
• When only one instance of an entity is on the left , and more than one instance
of the entity on the right associated with the relationship than it is called one to
may relationship .
• For example :- Scientist can invent many inventions , but the invention is done
by the only specific scientist.
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18. MANY-TO-ONE RELATIONSHIP
:-
• When more than one instance entity of the left and only one instance of entity on the
right is called many-to-one relationship .
• For Example :- Student enroll for one course , but a cource have many students .

19. MANY-TO-MANY RELATIONSHIP
• When more than one instance of the entity on the left , and more than one
instance on the entity on the right than its called many-to-many relationship .
• For example :- Employee can assigned by many projects and project can have
many employee .
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